Geared-turbine system



C. A. PARSONS, S. S. COOK AND L. M. DOUGLAS.

GEARED TURBINE SYSTEM.

APPLICATION FILED'OCT. 31, 19l8.

ll ti CHARLES ALGERNDN PARSONS, STANLEY SMITH COOK, AND LOUIS MORTIMER DOUGLAS, OF NEWCASTLE-ON-TYNE, ENGLAND; SAID 000K AND SAID DOUG}- LAS ASSIGNORS T0 SAID PARSONS.

Gl-JEABEID-T'URBINE SYSTEML Specification of Letters Patent.

Patented May MD, 1921..

Application filed October 31, 1918. Serial No. 260,552.

To all whom it may concern:

Be it known that we, CHARLES ALGERNON PARsoNs, STANLEY SMITH Coon, and Louis MORTIMER DOUGLAS, all subjects of the King of Great Britain and Ireland, all residing at Heaton Works, Newcastle-on-Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in Geared-Turbine Systems, of which the following is a specification.

The present invention relates to geared turbine systems, in which a turbine transmits power through a double helical gear train.

As usually constructed turbines are provided with a thrust or adjusting block of the pivoted or ordinary type for the purpose of retaining the longitudinal position of the rotor relative to the stator. When such a turbine is driving a pinion having double helical gear teeth, it is necessary to pro vide a sliding coupling between the pinion and the turbine rotor, in order that each may take up its own longitudinal position, that of the turbine rotor being controlled by the adjusting block and that of the pinion by the intermeshing gear teeth.

Thrust blocks of the ordinary fixed collar type are frequently the cause of conslderable trouble in operation, and pivoted thrust blocks, although they are practically free from running troubles if properly constructed, are somewhat expensive to manu facture. lit is, therefore, desirable to dispense with adjusting blocks so far as is possible.

Sliding couplings have both the above mentioned disadvantages--they are very expensive to manufacture for high power, high speed shafts and they are frequently the cause of considerable trouble in run ning.

The object of the present invention is to overcome these difiiculties.

The invention consists in a geared turbine system in attaching the turbine rotor directly to the pinion shaft with a fixed cou-,

pling and causing the intermeshing double helical teeth of the pinion to determine the normal longitudinal position of the turbine rotor.

The invention also consists in obtaining approximate uniformity of distribution of pressure on the gear teeth by cutting the teeth of the two helices at difi'erent angles.

The invention also consists in the im: proved geared turbine arrangements hereinafter described.

The invention is illustrated by way of example in the accompanying drawing which shows an ordinary reaction turbine a hydrostatically balanced by an ordinary dummy piston, this turbine driving a double helical gear pinion c, (I through a fixed coupling 6, the forces acting on the teeth of the pinion causing the latter to control the longitudinal position of the turbine rotor. For convenience of adjustment a pad piece f may be provided between the coupling flanges of the pinion and rotor shafts g h. This pad piece can be machined to the thickness required to bring the turbine rotor into its correct mean position relative to the stator after the units are set up in place. The normal clearances between the journal shoulders and the bearings are preferably small in comparison with the axial clearance of the turbine blades, or of labyrinth packin of the dummy, or other internal parts.

Tn order to obtain as far as possible a uniform distribution of pressure across the pinion teeth and to balance the end thrust of the turbine, the helices 0 d are cut at diflerent angles to provide for the end thrust of the turbine a by means of the axial force which will be produced owing to the different angles of the helices.

In this installation; and all those in which the gears receive axial thrust from the turbine, the arrangement is preferably, but not necessarily, such that the turbine thrust is opposed to'the propeller thrust.

lit will be seen that in cases in whichtheturbine is to be exactly steam balanced and also in cases in which the unbalanced thrust is to be a determined quantity to suit the gear proportions adopted, means may be adopted for adjusting exactly the steam bal ance or thrust after the construction of the turbines. These means of adj u'stment should be permanent and may consist, in the case of a dummy piston, in connecting the leak-ofi' chamber behind the piston to a suitable stage of the turbine system which will give a back pressure insuring correct balance or thrust. As an alternative, the

area of the dummy leakage escape passage may be adjusted, or the blades may be slightly opened or closed or partly baflied by a covering plate.

Though a fixed rigid flange coupling is mentioned and shown on the drawings any coupling may be used which gives longitudinal and angular rigidity between the two elements.

Having now described our invention, what we claim as new and desire to secure by Letters Patent, is

A geared turbine system comprising in combination, a turbine rotor, a pinion shaft,

a fixed coupling between said rotor and 15 shaft, double helical teeth on said pinion out at different angles, the longitudinal po sition of said turbine rotor being determined by said helical teeth being cut at different angles, as and for the purpose set forth. 20 In testimony whereo'fwe have signed our names to this specification.

CHARLES ALGERNON PARSONS, STANLEY SMITH COOK, LOUIS MORTIMER DOUGLAS, 

